System of printed circuit boards

Abstract: Method for manufacturing contact elements from a strip of conductive material, wherein successive contact elements are formed in the strip by cutting away parts between the successive contact elements. Each contact element is made with a contact means with opposite contact faces for contacting a complementary contact element. The contact means of each contact element includes a twisted portion in such a manner that the contact means is twisted along an angle of substantially 90° with respect to the plane of the material strip.

Description: The invention relates to a system of printed circuit boards, comprising a central printed circuit board and further printed circuit boards at each side of the central printed circuit board. In EP-A-0 627 789 of the same date and same applicant a system of this type is described, wherein the further printed circuit boards are mutually crossing each other perpendicularly. The printed circuit boards are connected to each other by means of at least one connector assembly. In such a system contact pins are used with contact pin parts projecting from the central printed circuit board at both sides. Said projecting contact pin parts have contact faces for contacting complementary contact elements. In manufacturing such contact pins portions of a material strip between subsequent contact pins are cut away and due to this cutting step only two opposite faces of the contact pin parts are suitable for contacting complementary contact elements. EP-A-0 047 469 discloses a method for manufacturing contact elements with a contact pin part 1 including a twisted portion 3 at one end and a female contact element at the other end. The contact pin part 1 is inserted into a plated through-hole of a printed circuit board and the pin part 1 is used for wire-wrapping connections. US-A-3 530 422 discloses a connector with a housing having a plurality of contact elements wherein the contact elements are fixed in the housing by rotating a part of the contact element when the contact element has been inserted into the housing. The contact pin part of the contact element is used for wire-wrapping connections. The invention aims to provide a system of printed circuit boards wherein suitable contact faces are available for contacting complementary contact elements at both sides of the central printed circuit board. To this end the invention provides a system of printed circuit boards, comprising a central printed circuit board, a further printed circuit board at each side of the central printed circuit board, said further printed circuit boards mutually crossing each other perpendicularly, and a connector assembly connecting the printed circuit boards to each other, said connector assembly comprising a plurality of contact pins having two contact pin parts with opposite contact faces for contacting complementary contact elements of the connector assembly, wherein at each contact pin one contact pin part is twisted along 90° with respect to the other contact pin part. The invention will be further explained by reference to the drawings, in which Figs. a, b, c and d show successive steps of a method for manufacturing contact pins to be used in the connector assemblies of a system according to the invention. Fig. a shows two adjacent contact pins 1 formed out of a strip of conductive material, such as for example a suitable copper alloy, of which only a narrow band 2 is present connecting the successive contact pins with each other. The parts of the material strip lying between the successive contact pins 1 are cut away. As shown in Fig. a the intermediate parts are cut away in such a manner at the top side of the narrow band 2 that the contact pins have a shoulder portion 3 lying in the plane of the strip. Above this shoulder portion 3 each contact pin 1 has a contact pin part 4 with opposite contact faces 5 lying in the respective main planes of the strip and are therefore extending substantially parallel to the shoulder portions 3. These contact faces 5 are formed in a usual manner for contacting a complementary element. The faces of the contact pin parts 1 directed towards each other are not suitable for contacting a complementary contact element due to the cutting away of the intermediate parts of the strip. In the embodiment shown the contact pins 1 are provided at their lower side with a press fit portion 6 known per se, wherein a contact pin is adapted to be inserted into a hole of a printed circuit board with this press fit portion 6. This press fit portion 6 guarantees a good contacting of the wall of the hole plated with a conductive material, and holds the contact pin 1 in the hole. The shoulder portion 3 is provided to press the contact pin 1 in a suitable manner into the hole of the printed circuit board. The contact pin part 7 of each contact pin 1 opposite of the contact pin part 4 can also be provided with opposite contact faces 5 extending in the main planes of the material strip. Such contact pins 1 with two contact pin parts 4, 7 are suitable for applications wherein the contact pins should be contacted at both sides of a printed circuit board. In Fig. b it is indicated that in the embodiment shown the contact faces 5 of the contact pin parts 4 are advantageously plated with a noble metal, such as for example gold, when the contact pins 1 are still in the material strip. The coating layer 8 obtained is shown in the drawing by shading. Thereby a good contact with complementary contact elements can be guaranteed. Fig. c shows that the contact pin parts 4 are twisted along 90° with respect to the plane of the material strip when the contact pins 1 are still in the material strip. In this manner the contact pin parts 4 each include a twisted portion 9. Thereby it is obtained that the contact faces 5 extend transverse to the direction of the shoulder portions 3. Finally, the contact pins 1 are cut loose from the material strip as shown in Fig. d. A coating layer 8 of the contact faces of the contact pin parts 7 is schematically shown by shading in Figs. c and d. By means of the method described contact pins 1 are obtained wherein the contact faces 5 of the contact pin part 4 extend transverse to the shoulder portions 3. The contact pins 1 are thereby particularly suitable for application in connector assemblies in systems with a central printed circuit board, wherein printed circuit boards mutually crossing each other perpendicularly are connected to the central printed circuit board at both sides. Further, the contact pins 1 are very suitable for applications, wherein the contact pins must be closely spaced.

Claims: System of printed circuit boards, comprising a central printed circuit board, a further printed circuit board at each side of the central printed circuit board, said further printed circuit boards mutually crossing each other perpendicularly, and a connector assembly connecting the printed circuit boards to each other, said connector assembly comprising a plurality of contact pins (1) having two contact pin parts (4, 7) with opposite contact faces (5) for contacting complementary contact elements of the connector assembly, wherein at each contact pin (1) one contact pin part (4) is twisted along 90° with respect to the other contact pin part (7). System according to claim 1, wherein the surfaces of said contact pin part (4) lying in the plane of the strip are plated as contact faces (5) with a noble metal before twisting the contact pin part. System according to claim 1 or 2, wherein the contact pin (1) are cut loose from the strip after the twisting step.

Inventors: JONCKHEERE LUC, MORLION DANNY, JONCKHEERE, LUC, MORLION, DANNY
Applicants: FRAMATOME CONNECTORS INT, FRAMATOME CONNECTORS INTERNATIONAL
Application year: 1994
Main classification: H01R43
IPC codes: H01R43